#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <uv.h>

#ifdef _WIN32
#define PIPENAME "\\\\?\\pipe\\echo.sock"
#else
#define PIPENAME "/tmp/echo.sock"
#endif

uv_loop_t* loop;

typedef struct {
  uv_write_t req;
  uv_buf_t buf;
} write_req_t;

void free_write_req(uv_write_t* req) {
  write_req_t* wr = (write_req_t*)req;
  free(wr->buf.base);
  free(wr);
}

void alloc_buffer(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
  (void)handle;
  buf->base = malloc(suggested_size);
  buf->len = suggested_size;
}

void echo_write(uv_write_t* req, int status) {
  if (status < 0) {
    fprintf(stderr, "Write error %s\n", uv_err_name(status));
  }
  free_write_req(req);
}

void echo_read(uv_stream_t* client, ssize_t nread, const uv_buf_t* buf) {
  if (nread > 0) {
    write_req_t* req = (write_req_t*)malloc(sizeof(write_req_t));
    req->buf = uv_buf_init(buf->base, nread);
    uv_write((uv_write_t*)req, client, &req->buf, 1, echo_write);
    return;
  }

  if (nread < 0) {
    if (nread != UV_EOF)
      fprintf(stderr, "Read error %s\n", uv_err_name(nread));
    uv_close((uv_handle_t*)client, NULL);
  }

  free(buf->base);
}

void on_new_connection(uv_stream_t* server, int status) {
  if (status == -1) {
    // error!
    return;
  }

  uv_pipe_t* client = (uv_pipe_t*)malloc(sizeof(uv_pipe_t));
  uv_pipe_init(loop, client, 0);
  if (uv_accept(server, (uv_stream_t*)client) == 0) {
    uv_read_start((uv_stream_t*)client, alloc_buffer, echo_read);
  } else {
    uv_close((uv_handle_t*)client, NULL);
  }
}

void remove_sock(int sig) {
  (void)sig;
  uv_fs_t req;
  uv_fs_unlink(loop, &req, PIPENAME, NULL);
  exit(0);
}

int main() {
  loop = uv_default_loop();

  uv_pipe_t server;
  uv_pipe_init(loop, &server, 0);

  signal(SIGINT, remove_sock);

  int r;
  if ((r = uv_pipe_bind(&server, PIPENAME))) {
    fprintf(stderr, "Bind error %s\n", uv_err_name(r));
    return 1;
  }
  if ((r = uv_listen((uv_stream_t*)&server, 128, on_new_connection))) {
    fprintf(stderr, "Listen error %s\n", uv_err_name(r));
    return 2;
  }
  return uv_run(loop, UV_RUN_DEFAULT);
}
